1. Technical Field
This invention relates to aqueous surfactant solutions and to a combination thereof with neat soap to form cleansing bars and the like. This invention relates, too, to a process for achieving these compositions.
2. Background Art
The dispersing and emulsifying capacity of conventional soaps and, more particularly, the alkali metal salts of long-chain monocarboxylic or fatty acids, is impaired in hard water due to the tendency of the soaps to form calcium and magnesium salts of the fatty acids that reduce the cleansing power of the soaps and form an adhering, greasy precipitate in sinks, bathtubs and the like. Soaps used in hard water also evidence a persistent undesired adhesion to the skin of the user. Soaps, too, in hard or soft water, tend to irritate sensitive membranes such as those of the eye.
To overcome these shortcomings, synthetic detergent bars have been developed but these bars are not usually capable of processing with conventional soap making equipment; nor do they have the smooth, pleasant texture of soap. Further, these detergent bars are quickly used up due to their high water solubility.
Combination cleansing compositions in bar form, prepared from mixtures of soap and detergent, have been developed heretofore in an attempt to secure the preferred properties of soap and detergent while attempting to eliminate their adverse effects. It has, however, proven difficult to attain these objectives.
A preferred detergent employed and heretofore, for this purpose, has been sodium cocoyl isethionate, also known as "SCI". SCI is a popular lime soap dispersant. It is mild and well tolerated by those allergic to conventional soaps. SCI is commonly used in syndet bars to impart mildness, better rinsibility, and to eliminate hard water resistance and deposits, such as the adhesion of calcium and magnesium salts to tubs, sinks and skin.
The incorporation of SCI into soap bars, and into shampoos and cosmetic emulsions, where it is also used, has involved commercially, weigh-in of the desired proportions of soap, SCI in solid particulate form and homogenization by mechanical agitation of the mixture with the usual additives.
Where employed in conventional soap bar manufacture, more particularly, SCI is added as a fine particulate solid to the almagamator containing soap pellets or chips, known as the soap base. The SCI, in this fine particulate phase, is, however, a sternutatory, lacrimatory and tussive agent, and tends to be so readily transmitted in the atmosphere as to contaminate other products and compositions made contemporaneously in the same plant environment. While SCI is available in larger particle sizes, they are not capable of homogenization in the several processing stages employed in manufacture of combination bars and the like. Further, the homogenization effected, using even reduced proportions of 2 percent to 3 percent of SCI in combination bars, has not been satisfactory, in that the SCI remains detectable, the SCI and soap having different degrees of solubility that cause a grittiness or "sandy feel" in the product bar.
Were it possible, therefore, to provide a smooth, consistent, homogenous, combination detergent and soap bar in which the rate of solubility of the component detergent and soap is substantially integrated and in which the grittiness or "sandy feel" is, as a result, removed, and in which, at the same time, the proportions of detergent and soap may be varied widely without adverse effect, a significant advance in the state of the art would be achieved. If, in addition, the processibility of the product bar were improved, the advance would be even more material.